Processing steps such as polymerization reactions often require the utilization of a halogen containing polymerization catalyst. These catalysts however can leave residual amounts of halogen in the feedstock or polymeric resin which may cause deactivation of the typical hydrogenation catalyst. If subsequent hydrogenation of the feedstock is desired, the small amounts of halogen retained from prior exposure to the halogen containing catalyst presents a processing dilemma. The deactivation or poisoning of Group VIII metal catalysts by even minor halogen levels is well known. See Catalysis, Berkman, Morrell and Egloff, Reinhold, 1940, p. 400.
Hydrogenation is often desired for making lighter colored petroleum resins from previously polymerized olefins made by using Friedel-Crafts reagents such as AlCl.sub.3 as a catalyst. Hydrogenation after polymerization gives a lighter colored petroleum resin with superior adhesive properties and better age resistance to ultraviolet light.
Hydrogenation catalysts for making lighter colored resins have been previously described in U.S. Pat. Nos. 4,328,090 and 4,629,766. The catalysts are alumina supported sulfided nickel-tungsten or nickel-molybdenum compositions. These catalysts are directed to hydrotreating of resins produced by polymerization of unsaturated cyclic olefin and diolefins.
Other hydrogenation systems for resins containing aromatic rings use hydrogen (H.sub.2) gas with a catalyst comprising a combination of noble metals such as Pd, Ru, Rb, Re and Pt on a carrier. See U.S. Pat. No. 4,540,480.
Additional hydrogenation catalysts have been made with a variety of combinations of nickel, molybdenum, cobalt and tungsten on supports such as alumina or silica-alumina. These catalysts are often directed to hydrodesulphurization of petroleum residues. See Chemistry of Catalytic Processes, Gates, Katzer and Shuit, McGraw-Hill, 1979, p.438, Table 5-17. The preparation and the chemistry of activation with hydrogen of nickel catalysts supported on alumina has also been described in "Chemistry of Nickel-Alumina Catalysts"; Bartholomew, C. H., Farrauto, R. J., J. Catalysis, vol. 45, pp. 41-53 (1976).
A hydrodesulphurization catalyst for petroleum has been prepared from nickel and/or cobalt oxide with molybdenum and/or tungsten oxide with lanthanum and/or cerium oxide on alumina. U.S. Pat. No. 3,975,303. The catalyst was not directed toward a process of hydrogenation or hydrotreating in the presence of halogen. Resin hydrotreating catalysts have been prepared from nickel and/or cobalt oxide with molybdenum and/or tungsten oxide with lanthanum and potassium. U.S. Pat. No. 5,107,051.
There is a need however in the art for a catalyst that can hydrogenate and decolorize a petroleum resin or a feed stream in the presence of a halogen without using expensive elements such as tungsten or molybdenum.